#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define USER "USER"

int main(){
 //   char* who = getenv(USER);

 //   printf("user: %s\n",who);
    
    char* who = getenv(USER);
    if(strcmp(who,"root") == 0 ){
        printf("user: %s\n",who);
    }else{
        printf("权限不足\n");
    }
    return 0;
}
